The Ministry of Labour's inter-war Local Unemployment Index (LUI) mainly reported rates of unemployment, as percentages. They also listed the total number of persons insured, enabling the actual number unemployed to be calculated, but this was not broken down by sex and age. Between 1927 and 1936 the LUI was known to be imprecise because the unemployed counts included (a) workers insured under the Agricultural Scheme, (b) workers aged between 14 and 16 and (c) workers aged 65 and over, while the count of insured workers used as a divisor for the rate did not.

In January 1937 a 'New Series' of the LUI began in which the number recorded as unemployed excluded the above categories. All reports included figures for change in the total percentage unemployed over the preceding twelve months, and those given in the 1937 reports are based on an adjusted figure for the previous year. It is therefore possible for 1936 to compare the rates originally published with corrected rates for the same places and dates. The figures here are the unadjusted rates.